For a few weeks now this is going on. When the battery is below 30% and I start playing Heavy graphic intensive games like need for speed most wanted or infinity blade, the phone suddenly shuts off. If I press power button to turn it back on, it just shows low battery sign but if I press and hold power and home button to force it on, it turns on and the battery still shows like 30% or maybe lower, but obviously not 0. There is power but it just shuts off. If I'm not playing games, then the battery runs fine until below 20% and then I have screen wake issues. If I'm listening to songs, the songs are still playing through my headphones but the screen just doesn't wake up even after pressing the power button. I just have to force restart it by pressing home and power button. All these issues begin below 30% battery. Is it that the battery has reached end of life? My iPhone is still under warranty, can it be fixed for free? Will apple fix it or replace it? EDIT: If it is the battery issue, what you guys think of 2680Mah battery on eBay? Is it quite bigger in capacity than OEM battery and I don't mind getting that and replacing it myself. I saw a YouTube video to replace battery and it doesn't seem difficult. I have all the tools!